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std::deque::begin, std::deque::cbegin

From cppreference.com
< cpp‎ | container‎ | deque
iterator begin();
(until C++11)
iterator begin() noexcept;
(since C++11)
const_iterator begin() const;
(until C++11)
const_iterator begin() const noexcept;
(since C++11)
const_iterator cbegin() const noexcept;
(since C++11)

Returns an iterator to the first element of the container.

If the container is empty, the returned iterator will be equal to end().

range-begin-end.svg

Contents

[edit] Parameters

(none)

[edit] Return value

Iterator to the first element

[edit] Complexity

Constant

[edit] Example

#include <iostream>
#include <deque>
#include <string>
 
int main()
{
	std::deque<int> ints {1, 2, 4, 8, 16};
	std::deque<std::string> fruits {"orange", "apple", "raspberry"};
	std::deque<char> empty;
 
	// Sums all integers in the deque ints (if any), printing only the result.
	int sum = 0;
	for (auto it = ints.cbegin(); it != ints.cend(); it++)
		sum += *it;
	std::cout << "Sum of ints: " << sum << "\n";
 
	// Prints the first fruit in the deque fruits, without checking if there is one.
	std::cout << "First fruit: " << *fruits.begin() << "\n";
 
	if (empty.begin() == empty.end())
		std::cout << "deque 'empty' is indeed empty.\n";
}

Output:

Sum of ints: 31
First fruit: orange
deque 'empty' is indeed empty.

[edit] See also

returns an iterator to the end
(public member function) [edit]